John (died 23 March 1304), nicknamed Chiano, was the Judge of Arborea from 1297 to his death.

John
Judge/King of Arborea
Reign1297-1304
PredecessorMarianus II
SuccessorMarianus III and Andrew
Died23 March 1304
SpouseGiacomina della Gherardesca
IssueJoanna
Andrew, King of Arborea (illegitimate)
Marianus III, King of Arborea (illegitimate)
Names
  • John De Serra Bas
HouseCervera (Serra Bas branch)
FatherMarianus II, King of Arborea
MotherAnn Saraceno Caldera

He was the son and successor of Marianus II and reigned initially under the tutelage of Tosorat Uberti, a Pisan nobleman. Nino Visconti of Gallura having been deposed in 1288, John was the only judge and Arborea the only Judicate left on the island of Sardinia. Shortly after his succession, Pope Boniface VIII proclaimed a Regnum Sardiniae et Corsicae: Kingdom of Sardinia and Corsica. He named James II of Aragon King and paved the way for the invasion of the two islands.

John prepared to resist. In 1300, he ceded (or sold) to Pisa the third of Cagliari which he ruled, the silver mines, and, perhaps, part of the judicial demesne. This last – the alienation of public land – released the people to revolt (bannus consensus) and they did so, executing John and cutting out his tongue.

He married Giacomina (died 12 February 1329), daughter of Ugolino della Gherardesca, in 1287, on the advice of his father, though he already had sons through a liaison with Vera Cappai, of Villasalto. He was succeeded by his sons Andrew and Marianus. He left a legitimate daughter, Joanna, who died in 1308.

Preceded by Judge of Arborea
1297–1304
Succeeded by
Succeeded by